A british military helicopter apparently was hit by a missile saturday and crashed in basra , triggering a confrontation in which jubilant iraqis pelted british troops with stones , hurled firebombs and shouted slogans in support of a radical shiite muslim cleric .
But protesters , who have been calling for mr abhisit 's resignation , said they were worried about what the security forces would do to move them off the streets after a day in which troops were accused of firing live rounds into crowds throwing rocks and firebombs .